92 k1500 - Rough Idle

I just started driving the 92 k1500 that was my dads rig. I have it at school this week and am driving it now and kinda want this issue to be fixed.

I thought the issue was only when it is first fired up for the day, but it actually got worse when i drove it home from class a few minutes ago. Class was about a mile away. The idle will sound like its got an extremely large cam in it. Watching the tach it will go from idle at what looks about 800-900RPM down to 200, maybe even 100 almost sounding like it will die, and then back up again. and it will just sit there and do that. I can rev it up and it will idle normal for a second and then go back to doing that.

Its a 350 TBI. Engine is a fairly fresh GM crate engine. Id just like to know some things to try to get it to stop running like this! Thanks

It actually did die on me when i got to my last class just an hour ago. Pulled up parked. was preparing to shut it off and it started doing that again. it did it like 2 times and then died. It starts right back up after it dies too.

Start out with the IAC (idle air control valve.) and if not you also will want to take a look at the coolant temp sensor (on the intake manifold next to the thermostat housing) search the forums a little for more info on both (there are a lot of threads pertaining to both of these parts) and if you still have the issue also look up how to pull any codes that you may be getting from your check engine light if it is on.

I know there are not any codes coming from it. My dad had had it on his snapon modis computer and couldnt ever figure out what was the issue since it wasnt throwing any codes. Ill check out those 2 things and see what i can get from those.

Just replaced the IAC and it seemed like it was doing fine. I took it for a test drive and it started acting up again. After i got back it got me thinking. I have only noticed this happening once it warms up. So when i first start it up on a cold morning it will idle fine. After it gets to operating temperature and the day is a bit warmer out is when it will do it the worst. So, that being said.. should my next replacement be the Coolant Temp Sensor? or should i remove the entire throttle body and clean that with some throttle body cleaner i purchased from napa. Thanks guys! I think i will eventually get it! I have faith!:great:

I had similar problems on my Chevy Corsica. Every now and then it would throw code for the Coolant Temp. Sensor. It usually died at a red light after about 15 mintues of driving. If I stopped at a gas station and shut it off, it wouldn't restart unless I floored it. I replaced the Coolant Temp. Sensor and it runs fine.